<HTML><BODY><div><div>Yes, it is</div><div> </div><div>The command:</div><div> </div><div><em>$ clang++ -fopenmp foo.cxx -I/home/../usr/lib/llvm-10/include/openmp/ -L/home/../usr/lib/llvm-10/lib</em></div><div> </div><div>gives the error:</div><div><strong>/usr/bin/ld: cannot find /lib64/libpthread.so.0<br>/usr/bin/ld: cannot find /usr/lib64/libpthread_nonshared.a<br>clang-5.0: error: linker command failed with exit code 1 (use -v to see invocation)</strong></div><div> </div><div> </div><div> </div><blockquote style="border-left:1px solid #0857A6; margin:10px; padding:0 0 0 10px;">Среда, 23 декабря 2020, 5:02 +03:00 от Johannes Doerfert <johannesdoerfert@gmail.com>:<br> <div id=""><div class="js-helper js-readmsg-msg"><div><div id="style_16086889771404339896_BODY">Ok, closer. is there a symlink from libomp.so to libomp.so.5 in<br>/home/../usr/lib/llvm-10/lib ?<br>If not, create one. Then try:<br><br>clang++ -fopenmp foo.cxx -I/home/../usr/lib/llvm-10/include/openmp/ -L/home/../usr/lib/llvm-10/lib<br><br><br><br>On 12/22/20 8:00 PM, Керим Хемраев wrote:<div class="mail-quote-collapse">> $ clang++ -fopenmp foo.cxx<br>><br>> gives:<br>> foo.cxx:2:10: fatal error: 'omp.h' file not found<br>> #include "omp.h"<br>> ^~~~~~~<br>> 1 error generated.<br>><br>><br>> Then I try:<br>><br>> $ clang++ -fopenmp foo.cxx -I/home/../usr/lib/llvm-10/include/openmp/<br>><br>> this produces the error:<br>> /usr/bin/ld: cannot find -lomp<br>> clang-5.0: error: linker command failed with exit code 1 (use -v to see invocation)<br>><br>> The dir: -I/home/../usr/lib/llvm-10/include/openmp/ contains omp.h<br>><br>>> Среда, 23 декабря 2020, 4:56 +03:00 от Johannes Doerfert <<a href="/compose?To=johannesdoerfert@gmail.com">johannesdoerfert@gmail.com</a>>:<br>>><br>>> -fopenmp will add the -lomp, which will look for libomp.so in your<br>>> library path.<br>>><br>>> Again, libomp.so versioning is not related to clang versioning.<br>>><br>>> What is the output of<br>>><br>>> clang++ -fopenmp foo.cxx<br>>><br>>><br>>><br>>> On 12/22/20 7:33 PM, Керим Хемраев wrote:<br>>>> It seems I know where is my fault (it<br>>>><br>>>><br>>>> using clang 5.0 with libomp.so.5 is probably not going to work.<br>>>><br>>>> is was very obvious) but I can’t understand how can I link external library to clang.<br>>>><br>>>> In the folder /home/../usr/lib/llvm-10/lib I have a file called libomp.so.5 (as I understood it is a library of version 5) and I strongly believe that I need to link this library when parsing commands to clang++:<br>>>><br>>>> $ clang++ -fopenmp foo.cxx -I/home/../usr/lib/llvm-10/include/openmp/ -L/home/../usr/lib/llvm-10/lib libomp.so.5<br>>>><br>>>> gives me error:<br>>>> clang-5.0: error: no such file or directory: 'libomp.so.5'<br>>>><br>>>> How to link libomp.so.5 ? Can’t find it in google yet<br>>>><br>>>><br>>>>> Среда, 23 декабря 2020, 2:33 +03:00 от Johannes Doerfert < <a href="/compose?To=johannesdoerfert@gmail.com">johannesdoerfert@gmail.com</a> >:<br>>>>><br>>>>> I think libomp is still on version 5.0, (I know, I know).<br>>>>> It is not coupled to LLVM wrt. version numbers.<br>>>>><br>>>>> Last time I checked, LLVM build for debian (and Ububuntu)<br>>>>> came bundled with the OpenMP runtimes (for the host). That<br>>>>> means you should not need libomp-5-dev but just clang-10.<br>>>>> libomp-5-dev is useful if you *don't* want clang but still<br>>>>> target libomp, which is the LLVM OpenMP host runtime, from<br>>>>> gcc, thus use it as a replacement of libgomp.<br>>>>><br>>>>> All that said, doesn't `clang-10 -fopenmp ...` "just work"?<br>>>>><br>>>>> ~ Johannes<br>>>>><br>>>>><br>>>>> On 12/22/20 5:28 PM, Керим Хемраев wrote:<br>>>>>> Hi Johannes,<br>>>>>><br>>>>>> Thank you for response<br>>>>>><br>>>>>> It seems that I don’t have libthread. Moreover it is highly likely that omp.h and libomp.so that I used to provide as parameters to clang are not shipped with clang 5 :)<br>>>>>><br>>>>>> I think I should now forget about xeus-cling for a while and simply build the code with latest (or any) version of clang with OpenMP.<br>>>>>><br>>>>>> I’ve tried to do the following:<br>>>>>> $ sudo apt-get install clang-10<br>>>>>> $ sudo apt-get install libomp-5-dev<br>>>>>><br>>>>>> Now I want to find where are these packages were installed:<br>>>>>> $ find /usr -iname clang-10<br>>>>>> /usr/lib/llvm-10/bin/clang-10<br>>>>>> /usr/lib/cmake/clang-10<br>>>>>> /usr/share/doc/clang-10<br>>>>>> /usr/share/bash-completion/completions/clang-10<br>>>>>> /usr/share/lintian/overrides/clang-10<br>>>>>> /usr/bin/clang-10<br>>>>>><br>>>>>> $ find /usr -iname libomp-10-dev<br>>>>>> /usr/share/doc/libomp-10-dev<br>>>>>><br>>>>>> So I’m afraid that libomp-10-dev contains only some docs and there is no library libomp-10-dev.so (or something)<br>>>>>><br>>>>>> Could you please guide me how to properly install clang with OpenMP that I could build my test script?<br>>>>>><br>>>>>> I’m on Ubuntu 20.04, x64<br>>>>>> $ cat /etc/lsb-release<br>>>>>> DISTRIB_ID=Ubuntu<br>>>>>> DISTRIB_RELEASE=20.04<br>>>>>> DISTRIB_CODENAME=focal<br>>>>>> DISTRIB_DESCRIPTION="Ubuntu 20.04.1 LTS"<br>>>>>><br>>>>>>> Среда, 23 декабря 2020, 0:48 +03:00 от Johannes Doerfert < <a href="/compose?To=johannesdoerfert@gmail.com">johannesdoerfert@gmail.com</a> >:<br>>>>>>><br>>>>>>> Hi Kerim,<br>>>>>>><br>>>>>>> I tried to help below. Looking at xeus-cling I did not immediately see<br>>>>>>> why clang 5 is<br>>>>>>> required. If this doesn't work as described below, I might spend time<br>>>>>>> trying to get it<br>>>>>>> to run with clang 11 ;)<br>>>>>>><br>>>>>>> On 12/22/20 1:57 PM, Керим Хемраев via cfe-dev wrote:<br>>>>>>>> Hi,<br>>>>>>>><br>>>>>>>> I’m struggling with compiling simple OpenMP program with clang 5.0.0.<br>>>>>>>> Here is the code (foo.cxx):<br>>>>>>>><br>>>>>>>> #include "omp.h"<br>>>>>>>> #include <stdio.h><br>>>>>>>> int main ( void ) {<br>>>>>>>> #pragma omp parallel<br>>>>>>>> printf ( "thread %d \n " , omp_get_thread_num ());<br>>>>>>>> }<br>>>>>>>><br>>>>>>>> As I use clang as part of xeus-cling my clang installation is inside conda packages:<br>>>>>>>> $ which clang<br>>>>>>>> /home/tasik/miniconda3/envs/cling/bin/clang<br>>>>>>>><br>>>>>>>> As this clang package does’t have omp.h I provide additional directories to find omp.h and libomp.so<br>>>>>>>> To compile the code I use the command:<br>>>>>>>> $ clang -fopenmp -I/home/../usr/lib/llvm-10/include/openmp/ -L/home/../usr/lib/llvm-10/lib foo.cxx<br>>>>>>>><br>>>>>>>> And I get errors:<br>>>>>>>> /usr/bin/ld: cannot find /lib64/libpthread.so.0<br>>>>>>>> /usr/bin/ld: cannot find /usr/lib64/libpthread_nonshared.a<br>>>>>>>> clang-5.0: error: linker command failed with exit code 1 (use -v to see invocation)<br>>>>>>> The error basically means clang looks for the libthread libraries and<br>>>>>>> cannot find them.<br>>>>>>> Check on you system where they are and provide the path via -L to clang.<br>>>>>>> That might allow<br>>>>>>> you to proceed. That said, I don't think you are able to mix clang 5 and<br>>>>>>> llvm 10 as you<br>>>>>>> do now. The headers and libraries clang might pick up need to be<br>>>>>>> consistent (with the clang<br>>>>>>> version). At least, you need to make sure `omp.h` and `libomp.so` are<br>>>>>>> the ones shipped with<br>>>>>>> clang 5.<br>>>>>>><br>>>>>>> ~ Johannes<br>>>>>>><br>>>>>>><br>>>>>>>> I really need some help to undertand how to work with clang 5.0.0 OpenMP<br>>>>>>>> And I think that it is difficult to update clang’s version as xeus-cling requires mentioned 5.0.0 version...<br>>>>>>>><br>>>>>>>><br>>>>>>>> With respect,<br>>>>>>>> kerim<br>>>>>>>><br>>>>>>>> _______________________________________________<br>>>>>>>> cfe-dev mailing list<br>>>>>>>> <a href="/compose?To=cfe%2ddev@lists.llvm.org">cfe-dev@lists.llvm.org</a><br>>>>>>>> <a href="https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev" target="_blank">https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev</a><br>>>>>> С уважением,<br>>>>>> Керим Хемраев<br>>>>>> <a href="/compose?To=kerim.khemraev@mail.ru">kerim.khemraev@mail.ru</a><br>>>>>><br>>>><br>>>> С уважением,<br>>>> Керим Хемраев<br>>>> <a href="/compose?To=kerim.khemraev@mail.ru">kerim.khemraev@mail.ru</a><br>>>><br>><br>><br>> С уважением,<br>> Керим Хемраев<br>> <a href="/compose?To=kerim.khemraev@mail.ru">kerim.khemraev@mail.ru</a><br>></div></div></div></div></div></blockquote> <div> </div><div data-signature-widget="container"><div data-signature-widget="content"><div>С уважением,<br>Керим Хемраев<br>kerim.khemraev@mail.ru</div></div></div><div> </div></div></BODY></HTML>